1. Field of the Invention
The present invention relates to a system and apparatus for collecting fumes emitted from a torch cutting operation. The system is particularly adapted for collecting fumes associated with torch cutting of continuously casted leaded steel strands.
2. Description of the Related Art
Prior artisans have disclosed various techniques for collecting fumes, gases, or smoke that are emitted or otherwise generated during cutting operations in the manufacture of steel. During such manufacture, steel is typically cut or otherwise severed by a high temperature cutting torch. This cutting operation produces copious amounts of fumes, gases, and/or smoke. If leaded steel is being cut, the resulting fumes contain significant amounts of lead. Lead-containing dust is also produced from cutting operations. It is well known that lead poses significant health risks and so, efforts have been made to collect such fumes, gases, and dust.
In U.S. Pat. No. 4,724,895, Mulesa disclosed a fume control system for the continuous casting of leaded steel. Referring to FIG. 2 of that patent, Mulesa described a flume 66 that is operably connected to an exhaust manifold 68. Fumes generated from a torch cutting operation are said to be drawn into the flume and exhausted through outlets 67. Although satisfactory in some respects, there still remains a need for an improved technique and system for the collection of fumes emitted or associated with torch cutting operations, particularly in the manufacture of leaded steel.
A problem associated with collecting airflows, gases, or smoke containing airborne or otherwise entrained lead particles, is separation of the lead particles from the carrier gas, e.g., air. Upon separation, the lead particles fall from the carrier gas and typically form lead-containing deposits upon exposed surfaces. Formation and existence of such deposits significantly increases the risk of exposure to lead. The potential for disentrainment or separation of lead particles from a carrier gas is particularly great when the velocity of the carrier gas is relatively slow. Although airflow velocities across a ventilation or duct system can generally be increased by increasing the pressure differential created by a fan or blower driving the system, this approach increases the energy requirements of the fan or blower. As will be appreciated, this is undesirable, particularly for a large scale manufacturing operation. Accordingly, there is a need for a structure and technique for reducing the tendency of lead particles to separate from a carrier gas, and thereby increase the proportion of lead collected or recovered.
Another problem associated with the collection of airflows or gases from a torch cutting enclosure is reducing the escape of air or gases containing hazardous agents such as lead from the enclosure while retaining flexibility of use for the enclosure so that it may be used in conjunction with a variety of manufacturing processes. If the manufacturing process is a continuous one and so there is typically a continuous output of steel product to be cut, it is difficult to provide a sealed, or relatively so, enclosure for torch cutting of the steel product without the enclosure being specifically tailored in accordance with the particular configuration or shape of steel product. As will be appreciated, an enclosure that is effectively sealed and which receives a continuous feed of one type of steel product, perhaps a large or tall profile beam, would most likely not provide the same degree of sealing if the steel product were changed, such as to a low profile sheet-like product. Of course, an enclosure could be structurally modified between changes in product runs, such as by re-sizing openings in the enclosure through which the steel product passes, but this would result in additional time, labor, and expense. Accordingly, there is a need for a torch cutting enclosure which provides a relatively sealed interior, and yet which may accommodate a wide array of shapes and sizes of product brought into the enclosure, without a significant loss of sealing efficiency.